Ecthyma gangrenosum is a rare skin infection classically associated with Pseudomonas aeruginosa. We performed a retrospective study of all cases diagnosed with ecthyma gangrenosum from 2004-2010 in a university hospital in Mexico (8 cases, 5 female patients and 3 male patients, ages between 4 months and 2 years). The most common risk factor for ecthyma gangrenosum is neutropenia in immunocompromised patients. In previously healthy patients, immunological evaluation is important to rule out underlying immunodeficiency. Ecthyma gangrenosum in healthy patients has a high mortality rate and early diagnosis and aggressive antibiotic treatment is imperative as it can improve patients' prognosis.

Ecthyma gangrenosum (EG) is a rare skin infection classically associated with Pseudomona aeruginosa. It can be a potentially fatal systemic infection and can be a manifestation of an underlying clinical entity.1-3

We performed a retrospective study of all EG cases from 2004 to 2010 in a university hospital in Monterrey, Mexico.

CASE REPORT

We report 8 cases that occurred with 5 female patients and 3 male patients, ages between 4 months and 2 years. Four patients were apparently previously healthy at admission, and the other 4 had a degree of immunosuppression (hemophagocytic lymphohistiocytosis, undifferentiated embryonic liver sarcoma and desnutrition (Table 1)). All patients presented at our institution in a febrile state. They also had a history of erythema that progressed to pustules and ulcerations surrounded by erythema, some of them covered by a necrotic crust. Two patients had the lesions on the face, 3 on the extremities, 1 in the supraclavicular region, 1 in the gluteal region, and 1 on the face and extremities (Figures 1 and 2). Workup was significant for neutrophilia in 3 patients, neutropenia in 4 patients, thrombocytopenia in 7 patients, and thrombocytosis in 1 patient. Bacteria blood cultures from 7 patients grew Pseudomona aeruginosa. The patient with negative blood culture showed a positive result in the bacterial wound culture for Pseudomona aeruginosa. On immunological investigation, 2 of the apparently healthy children were diagnosed with granulomatous chronic disease, with dihydrorhodamine 123 (DHR). Seven patients received combination therapy (4 ceftazidime and amikacin, 2 imipenem and amikacin, 1 meropenem and amikacin, and 1 meropenem and ciprofloxacin) and 1 received monotherapy with imipenem. Five patients had favorable evolution, with resolution of the skin lesions and with close follow-up. Three patients (including the 2 previously healthy) died secondary to sepsis.

Table 1 Study of 8 cases with ecthyma gangrenosum

Case

Age/Sex

Localization

Previously healthy or immunocompromised

Laboratory findings

Hemoculture

Treatment

Outcome

1

9 months

Face

Previously healthy Granulomatous chronic disease

Neutrophilia Thrombocytopenia

+

Ceftazidime and amikacin

Favorable

2

10 months Male

Extremities

Previously healthy Granulomatous chronic disease

Neutrophilia Thrombocytosis

+

Ceftazidime and amikacin

Favorable

3

13 months Female

Face

Immunocompromised Desnutrition

Leukopenia Thrombocytopenia

+

Imipenem

Favorable

4

5 months Female

Gluteal region

Immunocompromised Hemophagocytic lymphohistiocytosis

Neutropenia Thrombocytopenia

+

Ceftazidime and amikacin

Favorable

5

5 months Female

Face and extremities

Immunocompromised Desnutrition

Neutrophilia Thrombocytopenia

+

Ceftazidime and amikacin

Deceased

6

4 months Female

Extremities

Previously healthy

Neutropenia Thrombocytopenia

-Skin culture +

Imipenem and amikacin

Deceased

7

2 years Female

Supraclavicular region

Immunocompromised Undifferentiated Embryonic Liver Sarcoma

Neutropenia Thrombocytopenia

+

Meropenem and ciprofloxacin

Favorable

8

6 months Male

Extremities

Previously healthy

Thrombocytopenia

+

Meropenem and amikacin

Deceased

Figure 1 Ecthyma gangrenosum. (A) Day 4 of hospitalization: patient presenting with erythema and edema on the left cheek. Lower lip showing ulceration with necrotic tissue; (B) day 7 showing new erythematous areas on the upper lip

Figure 2 Progression of ecthyma gangrenosum on the left arm. (A) Initial presentation with erythematous nodule; (B) increase in size of the area with erythema and ulceration; (C) Ulceration with central necrotic crust

DISCUSSION

The most common risk factor for EG is neutropenia in immunocompromised patients. Although it rarely occurs in previously healthy patients, 50% of these patients reveal a primary subclinical immunodeficiency or underwent recent antibiotic therapy.2,4 In previously healthy patients, the immunological evaluation is important to rule out underlying immunodeficiencies.2

Two types of EG have been described: the classical or bacteremic form, secondary to hematogenous spread; and the localized EG or nonsepticemic form, in which the lesion is located at the site of inoculation of the organism into the skin.1

Antibiotic therapy with spectrum for Pseudomonas aeruginosa includes aminoglycosides, third- and fourth-generation cephalosporins, β-lactam antibiotics, and broad-spectrum penicillins. In addition to the results of susceptibility tests for the isolate from the patient, local patterns of susceptibility for each hospital should be considered in the initial choice of treatment. Some studies comparing combination therapy with monotherapy reveal that the regimens do not affect mortality rates.5-7

Prognosis depends on the host and on the degree of immunosuppression.4 The disease has a high mortality rate. In patients with EG and septicemia secondary to Pseudomonas, it ranges from 38%-77%, and in patients with no sepsis, it is described in about 15%.8 The most important prognostic factor of mortality in invasive forms is the presence of neutropenia at diagnosis.9 Luigi et al. reported that severe sepsis by P. aeuruginosa can occur in previously healthy children with a mortality rate of 55%.10

Immunological evaluation is essential in all the patients (including the apparently healthy ones) as immunosuppression can drastically change the prognosis. EG in healthy patients has a high mortality rate and early diagnosis and aggressive antibiotic treatment is imperative as it can improve the patient's prognosis.

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